Module 3 - The Endocrine System

methods of hormone action

- control of enzymatic reaction rates - control of ion or molecule transport across cell membranes - control of electrical signaling pathways - control of gene expression and protein synthesis

The link between a first messenger and a second messenger in a cell that responds to peptide hormones is usually

G protein

ACTH

The pituitary hormone that controls the release of glucocorticoids from the adrenal cortex

When stimulated by a particular hormone, there is a marked increase in the activity of G proteins in the membrane. The hormone is probably: a steroid. a peptide. testosterone. estrogen. aldosterone.

a peptide

portal system

a specialized region of circulation consisting of two capillary beds directly connected by a set of blood vessels

ACTH target organ

adrenal cortex

primary source of aldosterone

adrenal cortex

primary source of epinephrine

adrenal medulla

The adrenal cortex produces a steroid hormone called ___________ that controls Na+ and K+ homeostasis and another steroid hormone called ___________ that controls blood glucose levels.

aldosterone, cortisol

post-translational modification

alterations to a protein molecule made after translation

derivatives of tyrosine

amino acid derived hormone

half-life

amount of time required to reduce the concentration of a hormone by half

primary source of prolactin

anterior pituitary

trophic hormone

any hormone that controls the secretion of another hormone

hypothalamic hormones

dopamine (prolactin inhibitor), TRH (TSH + prolactin), CRH (ACTH), somatostatin (GH inhibitor), GHRH (GH), GnRH (LH + FSH)

posterior pituitary

extension of neural tissue, stores and releases hypothalamic neurohormones (oxytocin and vasopressin)

Hormones acting through signal transduction pathways elicit a _____________ response compared to hormones that produce genomic effects.

faster

long-loop negative feedback

final hormone from endocrine gland feeds back to hypothalamus and anterior pituitary

LH + FSH (gonadotropins) target organ

gonads

steroid hormone

hormones made from cholesterol

In hormone signaling, the concept of synergism occurs when

hormones working together produce a larger effect than predicted.

prohormone

inactive protein containing one or more copies of a hormone

peptide hormone

lipophobic molecule that interacts with receptors on cell surface

GH target organ

liver

prolactin target organ

mammary gland

Chemical signals released into the blood by neurons are called

neurohormones

primary source of insulin

pancreas

The majority of hormones that function in the body are

peptide hormones

gonadotropin (LH and FSH)

peptide hormones from the the anterior pituitary that acts on the gonads

primary source of melatonin

pineal gland

steroid hormones cannot be...

stored in secretory vesicles

hypothalamic-hypophyseal portal system

takes neurohormones directly from the hypothalamus to the anterior pituitary

TSH target organ

thyroid

primary source of calcitonin

thyroid

short loop negative feedback

trophic hormone feeds back on hypothalamus

anterior pituitary is controlled by

trophic hormones from the hypothalamus

hypothalamic-hypophyseal portal system

trophic hormones reach the anterior pituitary through the portal system; trophic hormones enter the blood via the capillary bed in the hypothalamus, which feeds into portal vessels, which deliver the trophic hormones to the anterior pituitary's cells, which then secrete hormones into the anterior pituitary capillary bed for distribution to body

anterior pituitary

true endocrine gland of epithelial origin